A collet is generally received in a tapered bore of a chuck body, the collet being formed with a correspondingly tapered external surface enabling radial contraction when the collet is forced axially into the tapered bore. Conventionally, tapering of the chuck body and collet external surface proceed in the spindle direction, enabling a wide opening for insertion of the collet into the chuck bore. Moreover, this taper naturally centralizes the portion of the collet within the chuck bore. The remaining portion of the collet not within the tapered bore can be pushed from the central axis due to non-isotropic application of force resulting from the locknut threads, the locknut collet support angle and/or the collet being twisted as the locknut is tightened. Such misalignment from the central axis is translated to the rotary cutting tool producing unacceptable runout and/or vibrations that can damage the cutting tool and workpiece.